Project Summary The goal of this project is to significantly enhance our understanding and treatment of inadequate balance responses in the elderly and in patients with neurological impairments following external perturbations such as a slip or trip. Our laboratory studies have shown that balance responses can be improved with practice in the elderly and in patients with Parkinson's disease (PD). However, these laboratory studies have not been translated into clinical practice because there is currently no safe and reliable technology for training and quantifying balance responses, particularly during overground walking. The ZeroG gait and balance training system developed and now commercialized by Aretech, LLC (Ashburn, VA) allows individuals with gait and balance disorders to safety practice walking overground with concurrent body-weight support and fall protection. The current system does not allow patients to practice recovering from unexpected external perturbation for balance training nor does the system contain the necessary instrumentation for quantifying balance responses. In this Phase I SBIR, we will significantly enhance the capabilities of the ZeroG system by developing controlled balance perturbations of adjustable magnitude and direction that can be delivered during standing and overground walking. The framework for the ZeroG balance perturbation sequences, called TRIP (Train Responses in Postural Rehabilitation), will be based upon the scientific findings of our laboratory over the last decade. We will develop the specific perturbation characteristics needed to train postural stepping responses in people with balance deficits due to PD and work closely with physical therapists on usability and safety. Finally, we will determine the feasibility and clinical usability of the ZeroG TRIP system through questionnaire feedback from patients and therapists. Phase II of this SBIR will focus on additional technical development of the ZeroG TRIP system and subsequent clinical testing of the device. Specifically, we plan to develop and test innovative metrics of postural stepping responses for ZeroG TRIP using the body-worn sensors with the partnership between Aretech, LLC and APDM, Inc. We will also utilize the APDM sensors to track the patient's movements throughout the gait cycle so that we can automatically trigger the TRIP perturbation rather than having to manually trigger the perturbation. Finally, we will refine the user interfaces on both the touch screen computer and wireless tablet, making the controls intuitive for the user yet providing sufficient flexibility to control the perturbation sequences. The clinical testing during Phase II will focus on comparing improvements in balance responses and balance confidence after training with TRIP compared to ZeroG body-weight support walking in people with PD. The ZeroG TRIP system will enable physical therapists to safely and systematically assess and treat inadequate balance responses, which are a major contributor to falls, disability, and declining quality of life.